Braking system.



C. RENSHAW.

BRAKING SYSTEM.

APPLICATION FILED JULY 30.1914.

Patented Aug. 14, 1917.

2 SHEETS-SHEET 1.

fr r-" I l 1 WITNESSES: la /4M W M T5 m m m m Wm H dd mw W 5 J I Wu ATTORNEY C. RENSHAW.

BRAKING SYSTEM.

APPLICATION FILED JULY 30,1914.

Patented Aug. 14, 1917.

2 SHEETS-SHEET 2.

fade ba INVENTOR WITNESSES: gi 4M UNITED STATES PATENT OFFICE.

CLARENCE RENSHAW, F EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOR T0 WESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, A. CQRPORATION OF PENNSYL- VANIA.

BRAKING- SYSTEM.

To all whom it may concern:

Be it known that I, CLARENCE RENSHAW, a citizen of the United States, and a resident of Edgewood Park, in the county of Allegheny and State of Pennsylvania, have I invented a new and useful Improvement in Braking Systems, oi which the following is a specification.

My invention relates to systems of control for electric motors and it has special reference to auxiliary or emergency braking systerns for-electric railway vehicles and the like.

The object of my invention is to provide a simple, reliable and relatively inexpensive means independent of the regular braking apparatus whereby a vehicle may be reliably and efiectively retarded and brought to a full sto in case derangement or" the ordinary brahing system renders it inadequate to meet the emergency.

In control systems of the class to which my invention is applicable, namely, those having one or more pairs of motors permanently connected in parallel-circuit relation, it is possible to set up dynamic braking by merely actuating the main circuit reverser to reverse the electrical relations of the field windings. and armatures of the motors. With ordinary hand controlled systems, where the reverser is located within reach of the motorman and can thus be readily operated at any time this practice is followed to a considerab e extentin obtaining 35 emergency braking. In power-operated control systems, where the reverser is operated indirectly, it is also -foilowed if circumstances permit. Where suppiy-circnit voltage is used as the normai means of control ling or operating the reverser in systems of the latter sort, however, the voltage sometimes taii and thus prevent the op tion of the reverser the very emergency hrahing is desired. con ingencies ct this kind hy 'onai means of cperat' 7 one. the

designed.

According present invention, vide auXni-ary power-controilling,

ahiy fluid-pressure contreliing means, cperative from the respective ends the vehicle for moving the reverser Lu obtainhraking action. in operating the reverser under normal conditions, the circuits are in- Specification of Letters Patent.

Patented Aug. 14, 1917.

Application filed July 30, 1914. Serial No. 854,03.

terlocked in such manner that the reverser cannot be moved while the motors are using power, in acccrdance with customary Bracac chtain tice.

mic action, the means whi r 1 or; ting tne r verser raking under emerg o. to, but 1 secure the sameprstecoy mechanically connecting the handle of an auxiliary operating valve te that of one are independent of the intenociis Y the auxiliary control switch in such mare ner that the latter wiil he opened md PQYFQP will. he cut. of': from ali of the meters of the car er train before the reverser be thrown. Dynamic braking is thus immediately set up, and vehicie is readily topped or maintained at a safe speed in case it is traveling down a grade, even when the supply-circuit voltage has the accompanying drawings, Figure I is a diagrammatic view or an auxiiiary apparatns constructed in accordance with my invention; Fig. 2 is a diagrammatic view of the main circuits of a system of cont-r03 adapted for employment in my invention; Fig. 3 is a sectional detail View of a portion of the apparatus shown in Fig. 1; and,

chart of Fig; 5, which is of well-known form.

Referring to Fig. l of tie drawing, the apparatus here shown comprises a suitable source of energy such as a contr i resister CH of a familiar type for suppifing the uxiliary control circuits shown in Fig ni ity of ccntroi switches CS1 and Us referahly Q the v p q a; '2, prereraii'v iccateci as the respective ends or the vehicle, operating the reversing switch RS under emergency conditions; and a plurality of pipes or conduits E1 and E2 for respectively connecting the valve AVI and the valve AV2 to the operating cylinder of the reverser.

- The operation of the apparatus shown in Fig. 1, without regard to the electrical circuit changes effected thereby, may be described as follows:

When it is desired to dynamically brake the vehicle, either the valve AVI or the valve AV2, as the case may be, according to the direction of travel of the vehicle, is actuated to admit fluid pressure from the tank T through a'suitable check valve CV to the operating cylinder of the reversing switch RS, which is thus thrown to its reverse position.

For normal operation of the reverser, either the valve NVl or the valve NV2 is electrically actuated, in a manner hereinafter set forth in connection with Fig. 3. I

Referring now to Fig. 2 of the drawing, the main circuits here shown comprise a supply circuit conductor marked Trolley; a return circuit conductor, such as a track rail, marked Ground; a plurality of electric motors respectively provided with armatures A1, A2, A3 and A4, and field windings F1, F2, F3 'and F4; a plurality of motor-. controlling switches LS, M1, M2, JR, J and G, including resistor short-circuitin switches R1 and R2, RRl and BB2; an the reversing switch RS which is adapted to simultaneously reverse the electrical relations ofall of the field windings with respect to the corresponding armatures, in accordance with well-known practice. It

should be noted that the motors are permanently connected in parallel related pairs, thus providing a closed circuit which is adapted, without further circuit arrange merit, for dynamic. braklng, as will be understood. The motors are preferably mounted on a railway vehicle of any suitable type,

in the usual manner, which, for purposes of.

simplicity, is not specifically shown.

Referrin now to F g. 4, the auxiliary control site illustri ed comprise the control resis master controllers MC. whh located at the rele, and are severluralitv of recto ter revsrsers MR, d to occupy an reverse position; and CS2; a pin- "r respectively op- ;aotor controlling and a plurality of train-line c TL for connecting the master centre MG to the several magnet coils in one more asociated vehicies.

switches inclus've; cor-- .Rl to M2 and G are next closed, and switch J is The electrically-governed, fluid-pressure controlled switches which are employed in the control system illustrated are preferably of the construction shown in Fig. 3, and comprise essentially an energizing coil 1, which is adapted to electro-magnetically actuate a centrally-disposed magnetizable core 2, to the lower end of which a suitable valve member 2 is attached and is biased by a suitable spring 3 to close a passage 4 from the tank or reservoir T. An exhaust chamber 5 normally communicates with a second passage 6 which leads to the fluidpressure operated cylinder, of any well known type, for closing the switch. When the coil 1 is energized, the core 2 and valve 3 are actuated to admit fluid pressure from the passage 4 to the passage 6 and to close communication between the passage 6 and exhaust chamber 5. Although all of the switches illustrated in connection with my system of control are preferably of the type just described, it will be understood that, with the exception of the reversin switch valves marked NVl and N ,2, any other suitable type of switches may be employed in my invention.

Assuming the various circuit connections to be as shown in Figs. 2 and 4, the operation of the control systems illustrated may be briefly described as follows: Energy is supplied-from the control resistor CR to the control switch CS1 or the control switch CS2, as the same may be, to the corresponding controller MC when it has been moved to its initial position and thence, through conductor 11, contact member 12 of the master reverser, conductor 13, interlocking contact member 14 of the main circuit reverser RS, conductor 15 and the actuating coil of the switch LS to the conductor 16, which is connected to the negative side of the control resistor CR. In like manner, the switches M1 and J R are energized directly from the master controller, thereby completing a se ries connection of the parallel-connected pairs of motors with all of the accelerating resistors. As the controller is moved successively to its positions 5 and c, the resistor short-circuiting switches R1, R2, R111 and BB2 are closed, in a well-known manner, to gradually accelerate the motors. The transition of the pairs of motors from series to parallel relation is accomplished by the well-known bridging form of transition in which, as indicate'il in the sequence chart of Fig. 5, switch J I 111st closed to snort circuit all or the reel. or sections, switches JR and inclusive, are opened, switches then opened, the then circuit condition corresponding to the position 5 of the master controller. In positions f and g of the controller, the various resistor short-circuiting switches are again actuated in the manner similar'to that hereinbefore described, and the pairs of motors are disposed in full parallel relation, when the master controller assumes its position 9.

In case it is desired to dynamically brake the vehicle when the supply circuit voltage is available, it is only necessary to throw the master reverser IVIR to its reverse position 1' when, provided the master controller MO is momentarily moved to its first operative position a, a circuit is completed from the conductor 11 through contact member 1'? of the master reverser, conductor 18, interlocking contact member 19 of the maincircuit reverser and the actuating coil oi the magnet valve EVQ. The main-circuit reverser is thus thrown to its reverse position and dynamic braking will thereupon be set up when the master controller is returned to its 0% position. However, in case the supply circuit voltage has failed or it is impossible to conduct current to the magnet valve N371 or the valve NV2 for any other reason, it will be appreciated that such actuation of the main-circuit reverser is impossible. In such an emergency, either the auxiliary valve AVI or the valve AVQ, as the case may be, is actuated to accomplish the reversing of the field windings in the manner hereinbefore described. Simultaneously with the operation of the auxiliary valve, a cam surface 21 (Fig. 1) of the auxiliary valve employed engages a rod or other suitable movable member 22120 cause a separation of the movable member 23 of the corresponding control switch from its coiiperating stationary contact member 24. In this way, if, in the excitement of the moment, or to save a little time, the train operatordoes not return his master controller to the oil position, the disconnection of the motors from the supply circuit is effected. It will be understood that any other suitable means for opening the control switch, upon the manipulation of the auxiliary valve, may be employed. -All of the motor-controlling switches, being thus deenergized, will open, provided they have not already opened by reason of the failure of supply-circuit voltage, and two sets of local braking circuits are provided in the vehicle, whereby it may readily be retarded or held at a safe speed when descending a grade, as will be understood.

I do,not wish to be restricted to the specific arrangement of parts or structural details herein set forth, but 'desire that only such limitations shall be imposed as are indicated in the appended claims.

I claim as my invention:

1. In a system of control, the combination with a plurality of electric motors having V armature and field windings, control means for varying the electrical relations of said armature and field windings, fluid-operated means for operating said control means to a forward or a reverse position and electrical means for normally governing the operation of said fluid-operated means, of auxiliary power-controlling means for offecting the operation of said fluid-operated means to reverse the position of said control means and set up dynamic braking when the motors are driven by their own momentum.

2. In a system of control, the combination with a plurality of electric motors provided with field windings and armatures forming a closed circuit, a supply circuit, main motor circuits and auxiliary control circuits connected to said supply circuit, and fluidpressure-operated means normally employed for reversing the electrical relations of the field winding and the armature of each motor, of auxiliary fluid-pressure-controlling means for effecting the actuation of said first named means to set up dyifiimic braking when the motors are momentum driven and for substantially simultaneously breaking all of said motor circuit and said auxiliary bontrol circuits.

3. In a system of control, the combination with a railway vehicle adapted to be driven by a plurality of electric motors provided with field windings and armatures and forming a closed circuit, a supply circuit,

auxiliary motor control circuits connected to said supply circuit, and power-operated means normally employed for reversing the electrical relations of the field winding and armature of each motor, of auxiliary powercontrolling means operative from a plurality of points in the vehicle for efiecting the actuation of said first named means to set up dynamic braking when the motors are momentum driven and for substantially simultaneously breaking the auxiliary control circuits.

4. In a system of control, the combination with a railway vehicle adapted to be driven by a plurality of electric motors provided with field windings and armatures and forming a closed circuit, a supply circuit, auxiliary motor-control circuits connected to said supply circuit and fluid-pressure means normally employed for reversing the electrical relations of the field winding and the armature of each motor, of auxiliary fluid-pressure means operated from a plurality of points in the vehicle for effecting the actuating of said first named means to set up dynamic braking when the motors are momentum driven and for substantially by a lurality of electric motors provided with old windings and armatures forming a permanent closed circuit, fluid-pressure operated means normall employed for reversing the electrical re ations of the field winding and armature of each motor, a source of fluidpressure, and a ipe or conduit normally employed for con ucting fluid pressure from sa1d source to said means, of auxiliary fluid-pressure controllin means, operative from the respective en s of the vehicle, and auxiliary pipes or conduits for connecting said auxiliary means to said first means for effecting the actuation thereof to set up dynamic braking when the motors are momentum driven. Y

6. In a system of control, the combination with an electric motor having armature and field windings, control means for var ing the electrical relations of said field an armature windings, fluid-operated means for operating said control means to a forward .or a reverse position and; electrical means for normally governing the o eration of said fluid -operated means, of auxiliary power-controlling meansifor effecting the operation of said fluid-operated means to reverse the position ofsaid 'control means and set up dynamic braking when the motor is driven by its own momentum.

7. In a system of control, the combination with a supply circuit, a railway vehicle adapted to be driven by a plurality of electric motors provided with field windings and armatures forming a permanent closed circuit, main circuit resistors, a plurality of motor-controlling switches, inclu msistor short-circuiting switches, for c acting acceleration and normal 0 ration of the motors, a plurality of actuating magnet coils for said switches, a controller for governin the ener ation of said coils, a switc ing device or connecting said supply circuit to said controller, and a fluid-preesure operated device for reversing the electrical relations of the field winding and armature of each motor, of auxiliary fluidpressu're controlling valves located at the respective ends of the vehicle for opening said switching device and for efiectin the actuation of said fluid-pressure opera device to thereupon set u d am1c braking.

In testimony whereo have hereunto subscribed my name this 24th day of July, 1914.

CLARENCE RENSHAW.

Witnesses:

C. L. DAVIS, B. B. Hmm. 

